Ignition timing control means for internal-combustion engines



June 21, 1949. MALLQRY 2,473,805

IGNITION TIMING CONTROL MEANS FOR INTERNAL-COMBUSTION ENGINES Filed Aug. 31, 1948 JNVENTOR. War/an Mafia/y Arron/v57:

Patented .Fune 21, 1949 rem caries IGNITION TIMING CONTROL MEANS FOR INTERNAL-COMBUSTIQN ENGINES Marion Mallory, Detroit, Mich.

Application August 31, 1948, Serial No. 47,008 6 Claims. (Cl. 123 -117) This invention relates to ignition timing control means for internal combustion engines.

The principal object of my invention is to control the pressures in the intake passageway of an internal combustion engine so that a single suction operated device will retard the spark timing when the engine is idling, advance the spark timing when the engine is working under light loads and reduce the advance of the spark timing when the engine is working under full loads; thereby eliminating the commonly known centrifugal governor used in present day ignition systems. I

Fig. 1 is a sectional view partly in elevation showing the mechanism of my ignition timing control means for internal combustion engines.

The elements showing in the drawings and illustrating my invention are referenced as follows: carburetor housing I, intake passageway 2, air inlet end 3, fuel mixture outlet 4 to the engine intake manifold, Venturi 5, fuel nozzle 6, butterfly throttle valve 1 fixed on shaft 8 whichis journalled in housing I, crank arm 9 fixed on shaft 8, throttle rod I connected to crank arm 9 for opening and closing throttle valve 1, orifice H in intake passageway 2 on the engine side of throttle valve 7, passageway l2 connecting orifice H to conduit i3, air bleed orifice l4 communicating with passageway l2 through passageways l5 and I6, valve I! for controlling communication between port M and passageway l2, crank arm I8 fixed on shaft 8, pin l9 fixed on crank l8 and interengaging valve H in arcuate slot 20.

The timing mechanism is conventional and as shown consists of the usual rotatable cam 2| which operates the electrical circuit breaker 22. The circuit breaker 22 is mounted on the plate 23 which can be rotated clockwise to advance the spark and counterclockwise to retard the spark. A suction device 24 is utilized for advancing and retarding the spark. The suction device comprises a flexible diaphragm 25 backed up by a compression coil spring 26. The diaphragm 25 is mounted in the housing 21 which is connected to the carburetor by conduit l3. The diaphragm is connected to plate 23 by connecting rod 28, one end of which is pivotally connected as at 29 to the plate 23 and the other end of which is fixed to the diaphragm. The wall 30 of the housing is perforated so that the diaphragm is subjected on the outside to atmospheric pressure; whereas on the inside of the housing 21, diaphragm 25 is subjected through conduit l3 and orifice H to the manifold vacuum obtaining at orifice l I. An orifice 35 in venturi 5 communicates by means of branch conduit 36 with conduit l3.

The operation of my ignition system is as follows: As shown in the drawing, throttle valve 1 is in idle position and at this time pin is contacts valve l! at the upper end of slot 20 so that valve I! is in open position permitting communication between passageway l2 and air bleed orifice [4. Even though the manifold vacuum is high in intake passageway 2 on the engine side of throttle valve 1, atmospheric air is bled to passageway l2 through orifice l4 and the vacuum at orifice II is nullified and the pressure obtaining in chamber 33 is atmospheric. Orifice 35 also acts as an air bleed to orifice H when throttle valve 1 is in idle position.

As the throttle l is moved toward an open position, pin l9 will move downwardly and valve l'l, due to gravity, will close passageway I6 thereby cutting off communication between orifice M and passageway l2. Valve ll, if desired, can be provided with a spring for closing the same. Since air bleed orifice I4 is closed, the intake manifold vacuum obtaining at orifice ll as bled down through orifice 35 will now establish itself in suction chamber 33 thereby causing suction device 24 to advance the spark in accordance with the pressure conditions obtaining at orifices II and 35. As throttle l is moved from idle toward open position, valve l1 closes ofi air bleed H but even though orifice II is in the intake manifold, suction device 24 will not be subjected to the maximum manifold vacuum because orifice II will be air bled through orifice 35 and conduits 36 and I3..

suction device 24 will be subjected to the highest vacuum at a point when the throttle valve has opened just beyond idle position and the spark will be advanced to its farthest point under this condition. As the throttle I moves further toward open position, the vacuum at orifice H decreases because opening of throttle bleeds the manifold. This decrease in vacuum causes the spark advance to be reduced as the load is increased on the engine. However, as the throttle is opened the speed of air increases through Venturi 5 which maintains enough suction at orifice 35 (which establishes itself in chamber 33) to advance the ignition timing for wide open throttle and full load operation. Thus, at idle and part throttle orifice 35 serves as an air bleed to orifice I I but at wide open throttle orifice 35 ceases to act as an air bleed orifice and becomes a suction orifice and in general the Venturi suction created by the flow intake passageway, a throttle valve in the intake passageway controlling the flow oi motive fluid therethrough, an ignition timer, a suction device for actuating said ignition timer to advance and retard the spark, an orifice located in said intake passageway always on the engine side or said throttle valve, a conduit connecting said orifice with the suction chamber of said suction device, said suction device being constructed and arranged so that upon a fall of pressure in the suction chamber the suction device tends to advance the spark and upon a rise in pressure in the suction chamber the suction device tends to retard the spark, an air bleed orifice communieating with said suction chamber, a valve controlling said air bleed orifice, and means for actuating said valve to open said air bleed orifice when the throttle valve is in idle position whereby the pressure in said suction chamber is bled down and the spark is substantially fully retarded.

2. The combination claimed in claim 1 including a venturi in the intake passageway on the atmosphere side of said throttle valve, an orifice in said venturi, a conduit connecting said orifice with the suction chamber of said suction device whereby at wide open throttle the pressure in said suction chamber is substantially controlled by the flow of fluid through said venturi by the orifice therein.

3. The combination claimed in claim 2 including a lost motion connection between the air bleed valve and the throttle valve whereby the air bleed valve is opened at idle position and fully closed at all other positions of the throttle valve.

4. In an internal combustion engine having an intake passageway, a throttle valve in the intake passageway controlling the fiow of motive fluid therethrough, an ignition timer, a suction device for actuating said ignition timer to advance and retard the spark, an orifice located in said intake passageway always on the engine side of said throttle valve, a conduit connecting said orifice with the suction chamber of said suction device. said suction device being constructed and arranged so that upon a fall of pressure in the suction chamber the suction'device tends to advance the spark and upon a rise in pressure in the suction chamber the suction device tends to retard the spark, resilient means acting on said ignition timer and tendins at all times to retard the spark, an air bleed orifice communicatin with said suction chamber, a valve controllin said air bleed orifice, and means for actuating said valve to open said air bleed orifice when the throttle valve is in idle position whereby the pressure in said suction chamber is bled down and the spark is substantially fully retarded.

5. The combination claimed in claim 4 including a venturi in the intake passageway on the atmosphere side 0! said throttle valve, an orifice in said venturi, a conduit connecting said orifice with the suction chamber 01 said suction device whereby at wide open throttle the pressure in said suction chamber is substantially controlled by the fiow oi iluid through said venturi by the orifice therein.

6. The combination as claimed in claim 5 wherein the ignition timer includes a cam rotated in accordance with the speed of the engine, a breaker arm carrying a contact, a relatively stationary contact, movable supporting means for said breaker arm and relatively stationary contact, said supporting means being adjustable angularly about said cam, and a connection between said supporting means and the suction device whereby the suction device adjusts the supporting means angularly about said cam to advance or retard the spark.

MARION MALLORY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,268,490 Mallory Dec. 30, 1941 2,269,279 Mallory Jan. 6, 1942 2,365,768 Mallory Dec. 26, 1944 

